feat: add one-click startup scripts for project management

- Add start.sh/start.bat for one-click startup (backend + frontend)
- Add stop.sh/stop.bat for stopping all services
- Add restart.sh for restarting services
- Add status.sh for checking service status
- Add Makefile with convenient management commands
- Add comprehensive documentation (ONE_CLICK_START.md)
- Update README with one-click startup instructions

Features:
- Automatic environment checking (venv, node_modules)
- Process management with PID tracking
- Unified log management (logs/*.log)
- Health checking after startup
- Support for Linux, macOS, and Windows
- No more need for multiple terminal windows

Usage:
  ./start.sh      # Start all services
  ./stop.sh       # Stop all services
  ./status.sh     # Check service status
  ./restart.sh    # Restart services
  make start      # Alternative using Makefile

Benefits:
- One command instead of multiple terminals
- Automatic environment validation
- Centralized logging
- Process lifecycle management
- Developer-friendly output messages

stop.bat

@@ -0,0 +1,39 @@
+@echo off
+REM ERP AI Assistant - Windows 停止脚本
+
+echo ========================================
+echo    ERP AI Assistant - 停止中...
+echo ========================================
+echo.
+
+echo 查找并停止后端进程...
+for /f "tokens=2" %%i in ('tasklist ^| findstr /i "python.*app.main"') do (
+    echo 停止进程: %%i
+    taskkill /PID %%i /F > nul 2>&1
+)
+
+echo 查找并停止前端进程...
+for /f "tokens=2" %%i in ('tasklist ^| findstr /i "node.*vite"') do (
+    echo 停止进程: %%i
+    taskkill /PID %%i /F > nul 2>&1
+)
+
+REM 也尝试通过端口查找进程
+echo 检查端口占用...
+for /f "tokens=5" %%a in ('netstat -aon ^| findstr ":8000" ^| findstr "LISTENING"') do (
+    echo 停止后端进程: %%a
+    taskkill /PID %%a /F > nul 2>&1
+)
+
+for /f "tokens=5" %%a in ('netstat -aon ^| findstr ":5173" ^| findstr "LISTENING"') do (
+    echo 停止前端进程: %%a
+    taskkill /PID %%a /F > nul 2>&1
+)
+
+echo.
+echo ========================================
+echo    停止完成
+echo ========================================
+echo.
+
+pause